Multi-strand wire, such as high-voltage transmission wire, may be affected by defects known as “bird cage” defects, or “bird caging”. Bird caging in relation to wire defects typically refers to buckling of tensile armor wire strands of the multi-strand wire, resulting in an increase in radial deformation in pitch, shape, and/or circular diameter. This type of defect may cause problems in use of the multi-strand wire. For example, in power transmission applications, bird caging of electrical transmission lines may result in loss of voltage, wasted power, and even arc or flash-over resulting in power outages.
Bird caging may be caused by many factors, including, but not limited to, extreme axial compression (such as squeezing dead ends, compression fittings, in line sleeves, using 60 to 100 ton press heads), improper crimping of compression connecters, extreme bends in the wire, improper wire handling, ice buildup (expanding and separating strands of the wire), extreme heat, or lightning strikes.
Additionally, deformation of strands of the multi-strand wire may also be caused by roll-out of strands of the multi-strand wire from bad blocks, rollers, travelers, grounds, hoists, and/or slings.
Currently, if a bird cage or other deformation defect is found, operators typically attempt to hammer or press the strands back into the desired shape while the wire is in a suspended and/or connected state. If the deformation cannot be corrected, the multi-strand wire must be disconnected from support towers, removed, and replaced. In power transmission applications, this may mean that entire stretches of transmission line must be replaced and re-strung, at great expense of materials and labor.
To this end, a need exists for an apparatus and method for correcting deformation of multi-strand wire. It is to such apparatus and method that the inventive concepts disclosed herein are directed.